Alloy steels



Patented Nov. 17, 1931 'UNITED STATES PATENT GFFICE WALTER R. BREELER, 013 DETROIT, MICHIGAN .v ALLOY STEELS No Drawing.

vide a new alloy steel that may heimelyi machined and thereby brought to a desired configuration, and ther a example, by the nitriding process.

A further object of the invention is to provide a new alloy steel which is relatively low in cost, that has the property of free machinability and that may be hardened, as for example, by the nitriding process, without distortion.

Other objects of the invention will be apparent to those skilled in the art after reading the'specification.

Alloy steels at present in use and that are for susceptible of being hardened by the nit'riding process, possess only ordinary machining qualities and are not suitable for fast produc- 7 tion work. The new alloys described herein possess the advantage over the known nitritable steels in that after casting or otherwise roughly shaping, they may be freely machined with a decided saving in cutting time and tool life, which feature has proved to be of considerable advantage in manufacturing as processes.

The new alloy may be made in the standard typesof furnaces, for example, in the open hearth furnace, or in the electric arc, grin; W or other types of furnaces. 40 To 9. sm e charge of open hearth or Bessemer steel or molten selected scrap steel, there is added to the charge of molten metal the desired quantities of alloying elements, either as ferro alloys or as the commercial forms of the desired elements, to bring: the analyses up to that of the desired final alloy; the final mixture may be made either in the furnace containing the molten metal, or in a ladle, and after a thorough mixing has been 9 accomplished the molten alloy is cast into Application filed .Tune 23 9 t0 serial No. 463,353.

suitable ingots for subsequent further shaping.

A general analyses of the new alloy, which may vary for special uses, is as follows- K Percent Carbon up to 1.00 A1um1num 0.5 to 2.00 Manganese 025 to2. 0 Sulphur 0 05 to 0. 5 M Phosphorus 005 to 0.10 11con up to 1.00 Chronnunnor elements having 0.50, to 3.50-- b up" to 0150 Vanad1um up to 0:50 (optional),

Zirconium up to 0.20 (optional)- Balance, iron. For a large number of uses, an alloy having the following composition has been found to be eminently satisfactory:

Per cent Ca rlpon .25 Aluminum 1 00 Alan anner: 1 20 Sulphur 0120 Phosphorus 0.05 licon 0 20 Chromium 1150 Molybdenum 1 50 Balance, iron.

To a charge of molten steel of a selected composition, or a charge of melted selected 1 scrap steel, or a mixture thereof, is added preferably as ferro alloys, the desired quana tities of aluminum, manganese, chromium, molybdenum, vanadium, zirconium, and su1 phur, the latter combined with either the aluminum or zirconium, or thes ulphu; may have been present in suiiicient quantity some ofthe fen-nalleys added Vt-O the, ,,s 1. The vanadium may be substituted in partor en- 3 tirely for the aluminum, chromiiun, or molybdenum. Also the chromium may be l V s ibstituted in part or entirely by elements ar setalleaaeaearlar a irconium also generally present either in the original chinability, and that may be hardened by charge of steel, or in the ferro alloys which nitriding, comprisingare added. The aluminum and manganese Carbon are present in substantially jefiualguantlties, Aluminum and the sul Jhur is mn in Manganes other steels used for this purpose, from about gggfigf one tenth to about one fifth of the aluminum. Chromium Per cent about 0.25

about 1.00

about 1.20

Sulphur about 0.20 about 0.05

about 0.20

about 1.50

Molybdenum about The chromium and molybdenum together are present in about twice the quantity of aluminum.

The function of the aluminum, chromium, molybdenum or vanadium, either singly or collectively, in addition to their known properties in alloy steels of this kind, is to. facilitate the hardening with nitrogen during the nitriding process. The manganese also facilitates the hardening by nitriding and also facilitates the combination of sul hu with the remain i mlements to pro, ucetthe zanw riyhtiu emiaehieahiliil loy stee s of the above type are relatively cheap, tough, and may be readily shaped and machined into the desired configuration, and may be hardened by the nitriding process, or other processes, by which they acquire a hard and durable surface. The nitriding may be successively practiced by heating from about 800 F. to about 1200 F. in a current of ammonia gas, which ay or may not be mixed with a hydrocar on gas, as desired.

I claim: 1. An alloy steel that may be cast, forged, or rolled, having the property of free machinability, and that may be hardened by nitriding, comprising i P t er cen Carbon in eflfectiveoamounts up to 0 Aluminum Manganese Sulphur Phosphorus Chromium 0.50 to Silicon in effectlve amounts up to Molybdenum in effective amounts up to Vanadium in effective amounts up to Zirconium in effective amounts up t Balance, principally iron.

Per cent Carbon in efiective amounts up to 1.00 Aluminum 0.5 to 2.00 Manganese 0.25 to 2.00 Sulphur 0.15 to 0.25 Chromium 0.50 to 3.00 Phosphorus 0.05 to 0.10 Silicon in effective amounts up to 1.00

Balance, principally iron.

3. An alloy steel that may be cast, forged, or rolled, having the property of free machinability, and that may be hardened by nitriding, comprising Per cent Carbon in eflfective amounts up to 1.00 Aluminum 1.00 to 2.00 Manganese 0.75 to 1.50 Sulphur 0.15 to 0.25 Molybdenum 0.10 to 0.40 Chromium 1 00 to 2.50

Balance. principally iron:

4. An alloysteel that may be cast, forged, or rolled, having the property of free ma- Balance, principally iron.

In testimony whereof I hereby afiix my 

